Runs, but not automatically.

Question

one day found everything melting . turned the temp. dial off and back to medium . started running again and run hours before stopped again and did not come back on till i played with the dial . sears guy said possible defrost timer or compressor ( drawing 1.6 amps vs. 1.0) . changed d. timer, no help . so fridge still runs couple hours and shuts off, ice starts melting and won't restart without playing with temp. dial?